Statement of the Technical Field
The inventive arrangements relate to radio transceivers and more particularly to power saving switching configurations for multi-band transceivers that use multiple harmonic transmitter filters.
Description of the Related Art
A PIN diode is a diode with a wide, un-doped or lightly doped intrinsic semiconductor region that resides between a p-type semiconductor and an n-type semiconductor region. Under conditions where the PIN diode has zero bias or is reversed biased, it has a relatively low capacitance such that it presents a high insertion loss to a radio frequency (RF) signal. However, when the PIN diode is forward biased with sufficient current it will have only minimal resistance to RF signals (e.g. about 1 ohm). Due to these characteristics, PIN diodes are often used to form RF switches.
One example switch configuration using PIN diodes comprises a series-shunt configuration. A series-shunt configuration PIN diode switch is conventionally used to achieve a relatively high isolation, which may be particularly important in high frequency applications, for example at or above 1 GHz. To achieve the relatively high isolation in a high power application, for example >10 W, a relatively high reverse bias voltage is used. The series diode and shunt diode of a particular switched path must be forward and reversed biased complementarily to minimize insertion loss and maximize isolation.
In transceivers, a transmit/receive (T/R) switch is often require to switch an antenna between the transmitter and receiver. However, switches (including PIN diode switches) are known to introduce insertion loss in the RF path. Such insertion loss will commonly range from 0.1 to 0.5 dB, depending on RF frequency, power levels, and so on.